Lucas De Marchi <lucas.demarchi@xxxxxxxxxxxxxx> writes: > Hi Rusty, > > On Mon, Mar 18, 2013 at 11:32 PM, Rusty Russell <rusty@xxxxxxxxxxxxxxx> wrote: >> Andy Lutomirski <luto@xxxxxxxxxxxxxx> writes: >>> On Sun, Mar 17, 2013 at 7:24 PM, Rusty Russell <rusty@xxxxxxxxxxxxxxx> wrote: >>>> Andy Lutomirski <luto@xxxxxxxxxxxxxx> writes: >>>>> On Thu, Mar 14, 2013 at 10:03 PM, Rusty Russell <rusty@xxxxxxxxxxxxxxx> wrote: >>>>>> Err, yes. Don't remove module parameters, they're part of the API. Do >>>>>> you have a particular example? >>>>> >>>>> So things like i915.i915_enable_ppgtt, which is there to enable >>>>> something experimental, needs to stay forever once the relevant >>>>> feature becomes non-experimental and non-optional? This seems silly. >> ... >>>>> Having the module parameter go away while still allowing the module to >>>>> load seems like a good solution (possibly with a warning in the logs >>>>> so the user can eventually delete the parameter). >>>> >>>> Why not do that for *every* missing parameter then? Why have this weird >>>> notation where the user must know that the parameter might one day go >>>> away? >>> >>> Fair enough. What about the other approach, then? Always warn if an >>> option doesn't match (built-in or otherwise) but load the module >>> anyways. >> >> What does everyone think of this? Jon, Lucas, does this match your >> experience? >> >> Thanks, >> Rusty. >> >> Subject: modules: don't fail to load on unknown parameters. >> >> Although parameters are supposed to be part of the kernel API, experimental >> parameters are often removed. In addition, downgrading a kernel might cause >> previously-working modules to fail to load. > > I agree with this reasoning > >> >> On balance, it's probably better to warn, and load the module anyway. > > However loading the module anyway would bring at least one drawback: > if the user made a typo when passing the option the module would load > anyway and he will probably not even look in the log, since there's > was no errors from modprobe. > > For finit_module we could put a flag to trigger this behavior and > propagate it to modprobe, but this is not possible with init_module(). > I can't think in any other option right now... do you have any? No good ones :( MODULE_PARM_DESC isn't compulsory, so you can't rely on that to tell you about option names. Even if we had a flag, how would you know to set it? I guess you could try without then try with, and if it works the second time print a warning about typos. But it's still pretty ugly. We could implement such a flag with a fake "IGNORE_BAD_PARAMS" parameter, for example. That would fail nicely on older kernels, too. Hmmm.... Rusty. -- To unsubscribe from this list: send the line "unsubscribe linux-kbuild" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
